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ScrollableControl.AutoScroll Property

  • Reference

Definition

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll

Gets or sets a value indicating whether the container enables the user to scroll to any controls placed outside of its visible boundaries.

public:
 virtual property bool AutoScroll { bool get(); void set(bool value); };
public virtual bool AutoScroll { get; set; }
member this.AutoScroll : bool with get, set
Public Overridable Property AutoScroll As Boolean

Property Value

Boolean

true if the container enables auto-scrolling; otherwise, false. The default value is false.

Examples

The following code example shows how horizontal and/or vertical scroll bars are provided automatically as needed when the AutoScroll property is set to true. To run the example, follow these steps:

  1. Create a new Windows Forms application.

  2. Add a Panel to the form.

  3. Add a TextBox to the panel and name it text1.

  4. Move the text box so that the right part extends beyond the right edge of the panel.

    You should see only an outline of the part of the text box that is outside the bounds of the panel. If the whole text box is visible, the text box is on the form and not in the panel.

  5. Add a Button to the form.

  6. Add a handler for the Click event of the button.

  7. Add the following example code and call it from the button's Click handler.

When you run the example, you can only see the part of the text box that is inside the boundaries of the panel. When you click the button, you will see a horizontal scroll bar appear that will enable you to see the rest of the text box.

If you position a part of the text box below the bottom of the panel, you will see a vertical scroll bar when you click the button.

The example code checks to see whether the text box is outside the bounds of the panel before it sets the AutoScroll property to true, and before it sets the AutoScrollMargin property. This out-of-bounds check is not required. If AutoScroll is set to true, no scroll bars will appear when the text box is completely within the panel. Also, you can leave the margins at their default settings of 0,0.

void SetAutoScrollMargins()
{
   /* If the text box is outside the panel's bounds, 
          turn on auto-scrolling and set the margin. */
   if ( text1->Location.X > panel1->Location.X || text1->Location.Y > panel1->Location.Y )
   {
      panel1->AutoScroll = true;

      /* If the AutoScrollMargin is set to less 
                than (5,5), set it to 5,5. */
      if ( panel1->AutoScrollMargin.Width < 5 || panel1->AutoScrollMargin.Height < 5 )
      {
         panel1->SetAutoScrollMargin( 5, 5 );
      }
   }
}

private void SetAutoScrollMargins()
 {
    /* If the text box is outside the panel's bounds, 
       turn on auto-scrolling and set the margin. */  
    if (text1.Location.X > panel1.Location.X || 
       text1.Location.Y > panel1.Location.Y)
    {
       panel1.AutoScroll = true;
       /* If the AutoScrollMargin is set to less 
          than (5,5), set it to 5,5. */
       if( panel1.AutoScrollMargin.Width < 5 || 
          panel1.AutoScrollMargin.Height < 5)
       {
          panel1.SetAutoScrollMargin(5, 5);
       }
    }
 }

Private Sub SetAutoScrollMargins()
    ' If the text box is outside the panel's bounds,
    ' turn on auto-scrolling and set the margin. 
    If (text1.Location.X > panel1.Location.X) Or _
        (text1.Location.Y > panel1.Location.Y) Then
        panel1.AutoScroll = True
        ' If the AutoScrollMargin is set to less
        ' than (5,5), set it to 5,5. 
        If (panel1.AutoScrollMargin.Width < 5) Or _
            (panel1.AutoScrollMargin.Height < 5) Then
            
            panel1.SetAutoScrollMargin(5, 5)
        End If
    End If
End Sub

Remarks

When true, this property enables the container to have a virtual size that is larger than its visible boundaries.

Note

In Windows Forms when a child control is anchored to the right or bottom (Control contains Right or Bottom) the Container will behave as if AutoScroll were set to false.

There is currently a limitation in Windows Forms that prevents all classes derived from ScrollableControl from acting properly when both RightToLeft is enabled and AutoScroll is set to true. For example, let's say that you place a control such as Panel - or a container class derived from Panel (such as FlowLayoutPanel or TableLayoutPanel) - on your form. If you set AutoScroll on the container to true and then set the Anchor property on one or more of the controls inside of the container to Right, then no scrollbar ever appears. The class derived from ScrollableControl acts as if AutoScroll were set to false. Currently, the only workaround is to nest the ScrollableControl inside another ScrollableControl. For instance, if you need TableLayoutPanel to work in this situation, you can place it inside of a Panel control and set AutoScroll on the Panel to true.

Note

AutoScroll maintains the visibility of the scrollbars automatically. Therefore, setting the HScroll or VScroll property to true has no effect when AutoScroll is enabled.

Applies to

See also